There has been interest in incorporating nanometer sized crystalline semiconductors into glass matrices because nanoparticles are expected to increase the functionality of the composites. Nanoparticles are expected to add fast optical switching and optical nonlinearity capabilities. Other potential features of silicon-based nanoparticle composites include radiation and mechanical hardening, electromagnetic shielding, and optical activation.
Sol gel processes have been studied as processes to incorporate nanocrystal materials into glass matrices. The sol gel processes offer low temperature processing that typically provides homogenous composite materials. There have been attempts to incorporate silicon nano material into a silica sol-gel matrix, but stabilization of the Si nanoparticles photoluminescence (PL) properties has proved to be elusive.
Sol gel processes utilize a mixture of several chemicals and are sensitive to the nature of precursor components, solvents, catalysts and their pH value. See, Zhang et al., “Properties of Luminescent Si Nanoparticles in Sol-Gel Matrices,” 1998, J Sol Gel Sci Technol, 11:267-2. A known attempt to incorporate Si nanoparticles via a sol gel process using ethanol as a solvent led to quenching of the Si nanoparticles photoluminescence properties. Others have reported luminescence quenching with polar solvents and less, but still substantial quenching with non polar solvents.